RNA localization to nuclear speckles follows splicing logic

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Nuclear speckles are key membraneless organelles involved in RNA processing.
• Understanding RNA localization to nuclear speckles is crucial for deciphering gene expression regulation.

Purpose of the Study:

• To systematically characterize the sequence logic that determines RNA localization to nuclear speckles.
• To investigate the relationship between RNA speckle localization and RNA splicing.

Main Methods:

• Sequence analysis to identify features dictating speckle localization.
• Experimental validation of sequence elements and spliceosome interactions.
• Assessment of disease-associated variants' impact on speckle localization.

Main Results:

• Speckle localization is governed by sequence features resembling both exon and intron elements, even in non-spliced transcripts.
• Early spliceosome assembly interactions are critical for speckle localization.
• Disease-associated variants in exons reduce speckle localization.
• Speckle localization correlates with splicing kinetics and exon-inclusion/skipping decisions.

Conclusions:

• RNA speckle localization is intrinsically linked to pre-mRNA sequence features and early spliceosome complex formation.
• Speckle localization enhances splicing efficiency and is coupled to splicing kinetics.
• This work provides a model connecting RNA sequence, spliceosome assembly, and nuclear speckle localization.